1. Field of the Invention
This invention relates to wells and has particular reference to a wellhead assembly for oil and gas wells which is reversibly convertible for use in a variety of injection and production modes of operation.
2. Description of the Prior Art
In my U.S. Pat. No. 4,804,045, granted on Feb. 14, 1989, I disclosed and claimed a diversionary device for oil and gas wells designed to obviate the need for permanently mounting a conventional valve, or Christmas, tree arrangement on each injection or producing well. Such a valve tree is expensive and cumbersome, and the use of my diversionary device makes it possible to employ a single valve tree to service a number of wells. Thus, the valve tree need be temporarily mounted on a well only when maintenance or remedial work is to be performed thereon.
Such diversionary devices have met with considerable success and can be used on different wellhead assemblies adapted for different injection and production modes, which modes depend upon various factors such as well depth, oil viscosity, gas-oil ratios, etc. For example, certain wellheads are constructed or modified to permit free flow or artesian production. Others are constructed or modified to permit pumping by electrically operated submersible pumps. Others are constructed or modified for use with reciprocating rod pumps. Still others are constructed or modified for use in the injection of a fluid such as water or gas into a well to pressurize the underground oil or gas formation.
Over a period of time pumping conditions may change, thereby requiring replacement or modification of a wellhead assembly to adapt the same to a more appropriate injection or production mode for maintaining a desired degree of efficiency. This generally entails expensive reworking or replacement of the wellhead assembly, as well as a loss of expensive operating time while the well is out of operation.